(a) Field
The present disclosure relates to an organic light emitting element.
(b) Description of the Related Art
Organic light emitting diode (OLED) displays have received much attention as display devices for displaying images.
A conventional organic light emitting diode display includes a first substrate having an organic light emitting diode thereon and a second substrate disposed to face the first substrate and which protects the organic light emitting diode on the first substrate. The organic light emitting diode includes an organic emission layer for emitting light, and a first electrode and a second electrode that face each other, with the organic emission layer interposed therebetween.
The organic light emitting diode display may be classified into a top emission display, in which light emitted from the organic light emitting diode is irradiated in the direction of the second substrate, a bottom emission display, in which light emitted from the organic light emitting diode is irradiated in the direction of the first substrate, and a double-sided emission display, in which light emitted from the organic light emitting diode is irradiated in both the direction of the first substrate and the direction of the second substrate.
Among them, the organic light emitting diode of the top emission display has a structure in which the first electrode is light reflective and the second electrode is semi-transmissive. Such a top emission organic light emitting diode display has a microcavity structure.
The microcavity structure serves to improve the light efficiency (e.g., light emitting efficiency) of each red, green, or blue light (that is emitted by each organic emission layer) by implementing a kind of color filter effect. As a result, the thickness of each organic emission layer that emits red, green, or blue light is limited, and thus the thickness is determined (e.g., constantly determined) to suit the wavelength of a color of light which each organic emission layer emits.
However, when the thickness of the organic emission layer is thin (e.g., determined to be thin) to suit the wavelength of the color of the light that each organic emission layer emits, black spots and cell defectiveness occur due to sub-micrometer particles, which may be positioned on a surface of the first electrode.
The above information disclosed in this Background section is only to enhance the understanding of the background of the invention, and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.